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 * The Universal Permissive License (UPL), Version 1.0
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 * (a) the Software, and
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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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 * Software and the Larger Work(s), and to sublicense the foregoing rights on
 * either these or other terms.
 *
 * This license is subject to the following condition:
 *
 * The above copyright notice and either this complete permission notice or at a
 * minimum a reference to the UPL must be included in all copies or substantial
 * portions of the Software.
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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package com.oracle.truffle.jx.runtime;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.TruffleLanguage;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Cached.Shared;
import com.oracle.truffle.api.dsl.Fallback;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.interop.TruffleObject;
import com.oracle.truffle.api.interop.UnknownIdentifierException;
import com.oracle.truffle.api.library.CachedLibrary;
import com.oracle.truffle.api.library.ExportLibrary;
import com.oracle.truffle.api.library.ExportMessage;
import com.oracle.truffle.api.object.DynamicObject;
import com.oracle.truffle.api.object.DynamicObjectLibrary;
import com.oracle.truffle.api.object.Shape;
import com.oracle.truffle.api.strings.TruffleString;
import com.oracle.truffle.api.utilities.TriState;
import com.oracle.truffle.jx.JanivaLang;

/**
 * Represents an SL object.
 *
 * <p>This class defines operations that can be performed on SL Objects. While we could define all
 * these operations as individual AST nodes, we opted to define those operations by using {@link
 * com.oracle.truffle.api.library.Library a Truffle library}, or more concretely the {@link
 * InteropLibrary}. This has several advantages, but the primary one is that it allows SL objects to
 * be used in the interoperability message protocol, i.e. It allows other languages and tools to
 * operate on SL objects without necessarily knowing they are SL objects.
 *
 * <p>SL Objects are essentially instances of {@link DynamicObject} (objects whose members can be
 * dynamically added and removed). We also annotate the class with {@link ExportLibrary} with value
 * {@link InteropLibrary InteropLibrary.class}. This essentially ensures that the build system and
 * runtime know that this class specifies the interop messages (i.e. operations) that SL can do on
 * {@link JXObject} instances.
 *
 * @see ExportLibrary
 * @see ExportMessage
 * @see InteropLibrary
 */
@SuppressWarnings("static-method")
@ExportLibrary(InteropLibrary.class)
public final class JXObject extends DynamicObject implements TruffleObject {
  protected static final int CACHE_LIMIT = 3;

  public JXObject(Shape shape) {
    super(shape);
  }

  @ExportMessage
  boolean hasLanguage() {
    return true;
  }

  @ExportMessage
  Class<? extends TruffleLanguage<?>> getLanguage() {
    return JanivaLang.class;
  }

  @ExportMessage
  @SuppressWarnings("unused")
  static final class IsIdenticalOrUndefined {
    @Specialization
    static TriState doSLObject(JXObject receiver, JXObject other) {
      return TriState.valueOf(receiver == other);
    }

    @Fallback
    static TriState doOther(JXObject receiver, Object other) {
      return TriState.UNDEFINED;
    }
  }

  @ExportMessage
  @TruffleBoundary
  int identityHashCode() {
    return System.identityHashCode(this);
  }

  @ExportMessage
  boolean hasMetaObject() {
    return true;
  }

  @ExportMessage
  Object getMetaObject() {
    return JXType.OBJECT;
  }

  @ExportMessage
  @TruffleBoundary
  Object toDisplayString(@SuppressWarnings("unused") boolean allowSideEffects) {
    return "Object";
  }

  @ExportMessage
  boolean hasMembers() {
    return true;
  }

  @ExportMessage
  void removeMember(
      String member,
      @Cached @Shared("fromJavaStringNode") TruffleString.FromJavaStringNode fromJavaStringNode,
      @CachedLibrary("this") DynamicObjectLibrary objectLibrary)
      throws UnknownIdentifierException {
    TruffleString memberTS = fromJavaStringNode.execute(member, JanivaLang.STRING_ENCODING);
    if (objectLibrary.containsKey(this, memberTS)) {
      objectLibrary.removeKey(this, memberTS);
    } else {
      throw UnknownIdentifierException.create(member);
    }
  }

  @ExportMessage
  Object getMembers(
      @SuppressWarnings("unused") boolean includeInternal,
      @CachedLibrary("this") DynamicObjectLibrary objectLibrary) {
    return new Keys(objectLibrary.getKeyArray(this));
  }

  @ExportMessage(name = "isMemberReadable")
  @ExportMessage(name = "isMemberModifiable")
  @ExportMessage(name = "isMemberRemovable")
  boolean existsMember(
      String member,
      @Cached @Shared("fromJavaStringNode") TruffleString.FromJavaStringNode fromJavaStringNode,
      @CachedLibrary("this") DynamicObjectLibrary objectLibrary) {
    return objectLibrary.containsKey(
        this, fromJavaStringNode.execute(member, JanivaLang.STRING_ENCODING));
  }

  @ExportMessage
  boolean isMemberInsertable(String member, @CachedLibrary("this") InteropLibrary receivers) {
    return !receivers.isMemberExisting(this, member);
  }

  /** {@link DynamicObjectLibrary} provides the polymorphic inline cache for reading properties. */
  @ExportMessage
  Object readMember(
      String name,
      @Cached @Shared("fromJavaStringNode") TruffleString.FromJavaStringNode fromJavaStringNode,
      @CachedLibrary("this") DynamicObjectLibrary objectLibrary)
      throws UnknownIdentifierException {
    Object result =
        objectLibrary.getOrDefault(
            this, fromJavaStringNode.execute(name, JanivaLang.STRING_ENCODING), null);
    if (result == null) {
      /* Property does not exist. */
      throw UnknownIdentifierException.create(name);
    }
    return result;
  }

  /** {@link DynamicObjectLibrary} provides the polymorphic inline cache for writing properties. */
  @ExportMessage
  void writeMember(
      String name,
      Object value,
      @Cached @Shared("fromJavaStringNode") TruffleString.FromJavaStringNode fromJavaStringNode,
      @CachedLibrary("this") DynamicObjectLibrary objectLibrary) {
    objectLibrary.put(this, fromJavaStringNode.execute(name, JanivaLang.STRING_ENCODING), value);
  }
}
